There are a variety of conditions that require injection of fluids into, or withdrawing fluids from, parts of a body below the surface of the skin of the body. During the procedure, symptomatic gas embolism can occur when undissolved gas (e.g., air, CO2) accumulates in the heart and/or pulmonary arteries. This gas can compromise the circulation of blood through the lungs, causing serious injury or death.
Health Devices May–June 1996; 25(5–6):214-5 reported a case of suspected gas embolism. During a hysteroscopy (performed with a patient under intravenous sedation), the patient gasped for air almost immediately upon uterine insufflation. Based on the clinical signs, the medical staff suspected that the patient's condition was caused by a CO2 embolism that originated in the uterus. However, a follow up investigation revealed that the embolized gas was probably air, not CO2. The air may have been introduced into the patient from the dead space in the tubing set used to connect the insufflator to the hysteroscope. This tubing set was not purged before insufflation began. Health Devices recommended that before delivering a fluid to a patient, one must purge air from tubing sets and instruments. Thus, there is a need for a valved catheter wherein the valved catheter comprises a safety valve having substantially zero dead space built-in the catheter tube that would automatically close to reduce the risk of blood loss or air embolism if an attachment to the catheter were to be inadvertently disconnected from the catheter tube.
It is common to use an implanted catheter to repeatedly access the vascular system of a patient. A flexible guidewire placed in the vascular system can be used to facilitate placement of the catheter, but its use can prevent capping the catheter to prevent fluid loss from or air entering the vascular system during placement. After catheter placement, it is common to attach a valved cap to the catheter connector(s) to prevent fluid loss from or air entering the catheter and vascular system. U.S. Pat. No. 6,575,960 (Bleed Back Control Assembly and Method) relates to a Y-valved connector. The ‘Y-connector’ includes a sealing valve that is normally closed except when accessed with a small diameter tube or wire. The sealing valve does not completely prevent air or fluid leakage, but relies on a second user compressible valve to provide a complete seal.
In short, there are several problems with the current valves. The flow path through the valve is restricted due to a restricted cross-sectional area. There is a dead space above or below the valve where blood accumulates, which makes it difficult to clean the valve. The current valves are not designed for use with a guidewire traversing through the same valve. Also, the valves cannot be accessed multiple times; they are typically screwed on to the catheter and discarded after use.
Therefore, there is a need for a valved catheter that solves the above-mentioned problems and thereby reduces the risk of contamination and permits repeated use of the valved catheter for the life of the catheter which could be on the order of several years.